The Inconsistency of Arithmetic
Edward Nelson, a math professor at Princeton, is writing a book called Elements in which he claims to prove the inconsistency of Peano arithmetic.
It’s a long shot, but I can’t resist saying a bit about it.
I am writing up a proof that Peano arithmetic (P), and even a small fragment of primitive-recursive arithmetic (PRA), are inconsistent. This is posted as a Work in Progress at http://www.math.princeton.edu/~nelson/books.htmlThanks to David Roberts and Andres Caicedo for pointing this out on Google+.
A short outline of the book is at:
http://www.math.princeton.edu/~nelson/papers/outline.pdf
The outline begins with a formalist critique of finitism, making the case that there are tacit infinitary assumptions underlying finitism. Then the outline describes how inconsistency will be proved. It concludes with remarks on how to do modern mathematics within a consistent theory.
I have no idea if Nelson’s proof is correct! He has, however, done good mathematics in the past. For example, in his Ph.D. thesis he made major progress in constructive quantum field theory, by proving the self-adjointness of Hamiltonians for the ϕ 4 theory in 1+1 dimensions (with a spatial cutoff, I believe).
Over on Google+, Kevin Kelly asked:
His first sentence: “The aim of this work is to show that contemporary mathematics, including Peano arithmetic, is inconsistent, to construct firm foundations for mathematics, and to begin building on those foundations” reminds me of Gödel’s Theorem. Is it a fool’s quest to try to make an consistent arithmetic?I replied, trying to avoid nuances that would confuse nonmathematicians (so give me a break):
Most logicians don’t think the problem is “making a consistent arithmetic” - unlike Nelson, they believe they arithmetic we have now is already consistent. The problem is making a consistent system of arithmetic that can prove itself consistent.In his book Elements, in the chapter Against Finitism, Nelson explains his doubts about the principle of mathematical induction:
Gödel’s theorem says that given certain technical conditions, any system of arithmetic that can prove itself consistent must be inconsistent.
So, the only way out is to develop a system of arithmetic that doesn’t obey those ‘certain technical conditions’. And since Nelson is no fool, this is what he’s trying to do.
One of those ‘certain technical conditions’ is the idea that the numbers 0, 1, 2, 3, 4, … obey the principle of mathematical induction. Namely, if
A) some property holds for the number 0,
and
B) given that this property holds for some number n, it holds for the next number n+1,
then it holds for all numbers. Nelson doubts the principle of mathematical induction, for reasons he explains in his book, so I’m sure his new system will eliminate or modify this principle.
Needless to say, this is a radical step. But vastly more radical is his claim that he can prove ordinary arithmetic is inconsistent. Almost no mathematicians believe that. I bet he’s making a mistake somewhere, but if he’s right he’ll achieve eternal glory.
Induction is justified by appeal to the finitary credo: for every number x there exists a numeral d such that x is d. It is necessary to make this precise; as someone once said, it depends on what you mean by “is”. We cannot express it as a formula of arithmetic because “there exists” in “there exists a numeral d” is a metamathematical existence assertion, not an arithmetical formula beginning with ∃.[Here A x(d) is A with the free variable x replaced by the numeral d.]
Let A be a formula of P with just one free variable x such that ⊢ P∃xA. By the least number principle (which is a form of induction), there is a least number x satisfying A. One might, thinking that every number is a numeral, assert that there exists a numeral d such that ⊢ PA x(d).
But, as I learned from Simon Kochen, this does not work. The rank of a formula is the number of occurrences of ∃ in it. Let B be the formula asserting that there is no arithmetized proof of a contradiction all of whose formulas are of rank at most x. Then each B x(d) can be proved in P by introducing a truth definition for formulas of rank at most d. But if P is consistent then ∀xB is not a theorem of P, by Gödel’s second theorem. Now let A be B⇒∀xB. Then ∃xA is a theorem of P since it is equivalent to the tautology ∀xB⇒∀xB, but (if P is consistent) there is no numeral d such that ⊢ PA x(d).[namely, the axioms of Peano arithmetic, less mathematical induction]
The finitary credo can be formulated precisely using the concept of the standard model of arithmetic: for every element ξ of ℕ there exists a numeral d such that it can be proved that d is equal to the name of ξ; but this brings us back to set theory. The finitary credo has an infinitary foundation.
The use of induction goes far beyond the application to numerals. It is used to create new kinds of numbers (exponential, superexponential, and so forth) in the belief that they already exist in a completed infinity. If there were a completed in finity ℕ consisting of all numbers, then the axioms of P would be true assertions about numbers and P would be consistent.
It is not a priori obvious that P can express combinatorics, but this is well known thanks to Gödel’s great paper on incompleteness. As a consequence, exponentiation ↑ and superexponentiation ⇑ can be defined in P so that we have
(20) x↑0=S0
(21) x↑Sy=x⋅(x↑y)
(22) x⇑0=S0
(23) x⇑Sy = x↑(x⇑y)
and similarly for primitive-recursive functions in general. For the schema of primitive recursion to be coherent, it is necessary that the values of the functions always reduce to a numeral, since they are defined only for 0 and iterated successors of numbers for which they have been previously defined. Finitists believe that primitive recursions always terminate; for example, that applying (15)-(18)
and (20)-(23) a sufficient number of times,Note, in case it’s not obvious, that this is not a proof of the inconsistency of Peano Arithmetic. Nonetheless, exhibiting a recursion that doesn’t terminate sounds fascinating in its own right! I hadn’t been aware of this work of Bellantoni, Cook, and Leivant.
SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0⇑SS0
reduces to a numeral. But the putative number of times these rules must be applied can only be expressed by means of a superexponential expression — the argument is circular.
The problem is not simply that some primitive recursions are too long. The problem is structural: there is a sharp division between two classes of primitive recursions. This results from work of Bellantoni and Cook; see also Bellantoni’s thesis. They indicate that their work was strongly inuenced by previous work of Leivant, who subsequently gave a more elegant form to the characterization, and it is appropriate to call the result the BCL theorem.
While a number is being constructed by recursion, it is only potential, and when the recursion is complete, it is actual. What Bellantoni and Cook, and Leivant, do is restrict recursions so that they occur only on actual numbers. Then the theorem is that the class of functions computable in this way is precisely the class of polynomial-time functions. This is an astonishing result, since the characterization is qualitative and conceptually motivated, saying nothing whatever about polynomials, Bellantoni, Cook, and Leivant have revealed a profound difference between polynomial-time recursions and all other recursions. The recursions constructed by the BCL schema enjoy a different ontological status from recursions in general. In the former, recursions are performed only on objects that have already been constructed. In the latter, for example in a superexponential recursion, one counts chickens before they are hatched (and the chicks that they produce as well), all in the fond hope that this will eventually take place in the completed infinity by and by.
Not only is induction as a general axiom schema lacking any justification other than an appeal to ℕ as a completed infinity, but its application to specific variable-free primitive-recursive terms lacks a cogent justification. We shall exhibit a superexponential recursion and prove that it does not terminate, thus disproving Church’s Thesis from below and demonstrating that finitism is untenable.
He outlines his claimed inconsistency proof later, in Section 18 — but alas, it’s too technical for me to follow. It uses the fact (or claim) that Robinson arithmetic “proves the quasitautological consistency of its relativization”. It uses the “Hilbert–Ackermann theorem” stating that “a quasitautologically consistent open theory is consistent”. It also uses Chaitin’s incompleteness theorem, and Kritchmann and Raz’s “stunning proof without diagonalization or self-reference of Gödel’s second incompleteness theorem”. The only bit of this I understand is Chaitin’s incompleteness theorem.
Can anyone take a stab at explaining some of these ideas? You can see most of the proof sketch in his outline.
I should admit that Nelson and I had the same Ph.D. thesis advisor, so I probably take his ideas more seriously than if he were some random unknown guy. On the other hand, he turned me down when I asked him to supervise my undergraduate thesis, so it’s not like we’re best buddies or anything.
Sep 29, 2011 (2 days ago)
PhD film launches
PhD film launches
Nature (2011). doi:10.1038/nj7366-623d
Movie depicting PhD plight draws global attention.
Nature (2011). doi:10.1038/nj7366-623d
Movie depicting PhD plight draws global attention.
Sep 28, 2011 (3 days ago)
Youthpal bill
Sharng a guest column I wrote for India Today's Youth Special issue. Pasting below my original, slightly extended version.
Youthpal Bill
by Rashmi Bansal
If we want a Facebook or Google from India, we have to stop telling Johnny and Jyoti to "be good"
The moment I walked into Christ College, Bangalore I knew something was wrong. But I couldn’t quite put my finger on it. Until a student giggled and whispered to me, “You are wearing jeans. We are not allowed.”
College without jeans? That's like Dabbang without Salman. Is it even possible? The old fogies seem to think so!
Welcome to the brave new college campus where 'discipline' rules. Students will be less distracted if they are neatly dressed in t-shirts with collars and formal shoes. Girls, please don't leave your hair open and stick to salwar kameez. Now, nose in books!
Of course, we encourage innovation and entrepreneurship. Can't you see the shiny new incubation centre we have set up? Please - feel free to disregard conventional thinking and come up with the next Facebook or Google.
But no bunking classes, and complete your syllabus first. We are disabling the net connection after 12 midnight, because we care about your future more than you do.
Our college had 100% placement last year. Students got jobs in a wide variety of jobs which require very little thinking but everyone has at least heard of the company names. It looks good in our brochure.
We would very much like this trend to continue.
Across India, from Kota to Kakinada, I have visited college campuses where students are being moulded, into sheep. The kind of minds which will not think, or question but accept what is told to them. Instead of searching for answers from within.
'Be good and we will be good to you'. That is the unspoken letter of blackmail posted into young hearts by parents. Whether it's career choice or whom to marry, the Family Stamp of Approval still dictates dynamics. Surrender and you will get a pink laptop and study abroad and inherit the family business.
Who wants to be a rebel and lose all this?
And yet, in moments of darkness, moments of doubt, the Young Indian knows there is something more out there, waiting to be discovered. A hidden potential, a secret spark.
Ki hum bhi koi cheez hain, is duniya mein. Our time on this earth has made some difference.
I see a small but growing band of young Indians taking the path of idealism.
Breaking out of the 'Be Good' box and breathing free.
Some, leaving plum jobs to set up their own companies. Others, choosing the path of social entrepreneurship. Many more thinking and dreaming of such options.
“Please help me, guide me, mentor me…..” they write to me, after reading one or another of my books.
Very well, I say, but remember there are no shortcuts on the path of Self Actualisation. Unlike that Bournville chocolate you really have to earn it.
Do not be fickle, do not be weak. Be steady on the path, and persevere. Your life is your life, live it while you have it.
Or, wear Levi’s jeans and forever hold your peace.
Choose whichever path makes you happy. Just remember, you owe the same to your children. When it's their time, their day.
A note to Indian parents
Kahlil Gibran on Children
Your children are not your children.
They are the sons and daughters of Life's longing for itself.
They come through you but not from you,
And though they are with you yet they belong not to you.
You may give them your love but not your thoughts,
For they have their own thoughts.
You may house their bodies but not their souls,
For their souls dwell in the house of tomorrow, which you cannot visit, not even in your dreams….
My last word: Let your children live their dreams, not yours.
Youthpal Bill
by Rashmi Bansal
If we want a Facebook or Google from India, we have to stop telling Johnny and Jyoti to "be good"
The moment I walked into Christ College, Bangalore I knew something was wrong. But I couldn’t quite put my finger on it. Until a student giggled and whispered to me, “You are wearing jeans. We are not allowed.”
College without jeans? That's like Dabbang without Salman. Is it even possible? The old fogies seem to think so!
Welcome to the brave new college campus where 'discipline' rules. Students will be less distracted if they are neatly dressed in t-shirts with collars and formal shoes. Girls, please don't leave your hair open and stick to salwar kameez. Now, nose in books!
Of course, we encourage innovation and entrepreneurship. Can't you see the shiny new incubation centre we have set up? Please - feel free to disregard conventional thinking and come up with the next Facebook or Google.
But no bunking classes, and complete your syllabus first. We are disabling the net connection after 12 midnight, because we care about your future more than you do.
Our college had 100% placement last year. Students got jobs in a wide variety of jobs which require very little thinking but everyone has at least heard of the company names. It looks good in our brochure.
We would very much like this trend to continue.
Across India, from Kota to Kakinada, I have visited college campuses where students are being moulded, into sheep. The kind of minds which will not think, or question but accept what is told to them. Instead of searching for answers from within.
'Be good and we will be good to you'. That is the unspoken letter of blackmail posted into young hearts by parents. Whether it's career choice or whom to marry, the Family Stamp of Approval still dictates dynamics. Surrender and you will get a pink laptop and study abroad and inherit the family business.
Who wants to be a rebel and lose all this?
And yet, in moments of darkness, moments of doubt, the Young Indian knows there is something more out there, waiting to be discovered. A hidden potential, a secret spark.
Ki hum bhi koi cheez hain, is duniya mein. Our time on this earth has made some difference.
I see a small but growing band of young Indians taking the path of idealism.
Breaking out of the 'Be Good' box and breathing free.
Some, leaving plum jobs to set up their own companies. Others, choosing the path of social entrepreneurship. Many more thinking and dreaming of such options.
“Please help me, guide me, mentor me…..” they write to me, after reading one or another of my books.
Very well, I say, but remember there are no shortcuts on the path of Self Actualisation. Unlike that Bournville chocolate you really have to earn it.
Do not be fickle, do not be weak. Be steady on the path, and persevere. Your life is your life, live it while you have it.
Or, wear Levi’s jeans and forever hold your peace.
Choose whichever path makes you happy. Just remember, you owe the same to your children. When it's their time, their day.
A note to Indian parents
Kahlil Gibran on Children
Your children are not your children.
They are the sons and daughters of Life's longing for itself.
They come through you but not from you,
And though they are with you yet they belong not to you.
You may give them your love but not your thoughts,
For they have their own thoughts.
You may house their bodies but not their souls,
For their souls dwell in the house of tomorrow, which you cannot visit, not even in your dreams….
My last word: Let your children live their dreams, not yours.
Sep 27, 2011 (4 days ago)
Fluorescent bacteria keep secrets
Scientists develop fluorescent bacteria to display secret messages, creating a living invisible ink that could be used to combat counterfeiting.
Sep 27, 2011 (4 days ago)
Sorry: Tragic Events Help the Economy
Bad news, disastrous weather and war may all play a part in adding jobs.2:53 AM (3 hours ago)
92% of Top Ten Billboard Songs Are About Sex
Get your heads out of the gutters, America's musicians. We always knew that with all your nipple-showing and lesbian-kissing and crotch-grabbing that you're obsessed with sex, and today we have the science to back it up: "Approximately 92% of the 174 songs that made it into the [Billboard] Top 10 in 2009 contained reproductive messages," says SUNY Albany psychology professor Dawn R. Hobbs in Evolutionary Psychology. That's right--"reproductive messages," our newest favorite euphemism.
Those 174 top-selling songs were analyzed in order to determine how many sexy messages they contained in any of 18 sexy categories, including "arousal," "sexual prowess," and "genitalia." There was an average of 10.49 sex-related phrases per song, with R&B being head-and-shoulders(-and-maybe-some-other-body-parts) above the two other musical genres analyzed, country and pop. "Sexual appeal" was the most popular theme among both R&B and pop songs, while "commitment" (yawn) was most prevalent in country music.
He also discovered that sex sells: "further analyses showed that the bestselling songs in all three charts featured significantly more reproductive messages than those that failed to make it into the Top Ten," the report says. That's the trend that not only dated back to 1959 in American music, the study found, but one that goes all the way back to the classy days of opera: "While the frequency of some of the themes differ, these findings clearly show that the same reproductive categories derived from the content analysis of our initial sample of 2009 contemporary songs map surprisingly well onto the lyrics from opera and arts songs dating back hundreds of years."
Those 174 top-selling songs were analyzed in order to determine how many sexy messages they contained in any of 18 sexy categories, including "arousal," "sexual prowess," and "genitalia." There was an average of 10.49 sex-related phrases per song, with R&B being head-and-shoulders(-and-maybe-some-other-body-parts) above the two other musical genres analyzed, country and pop. "Sexual appeal" was the most popular theme among both R&B and pop songs, while "commitment" (yawn) was most prevalent in country music.
He also discovered that sex sells: "further analyses showed that the bestselling songs in all three charts featured significantly more reproductive messages than those that failed to make it into the Top Ten," the report says. That's the trend that not only dated back to 1959 in American music, the study found, but one that goes all the way back to the classy days of opera: "While the frequency of some of the themes differ, these findings clearly show that the same reproductive categories derived from the content analysis of our initial sample of 2009 contemporary songs map surprisingly well onto the lyrics from opera and arts songs dating back hundreds of years."
Sep 28, 2011 (3 days ago)
For women, risk of depression falls as coffee intake rises
A few cups of coffee a day may help keep the blues at bay. According to a large new study, women who drink caffeinated coffee are less likely to become depressed -- and the more they drink, the more their risk of depression goes down.Sep 27, 2011 (4 days ago)
West 'seeks to dismember' Syria
The Western nations are trying to create "total chaos" to break up Syria, the country's foreign minister tells the United Nations.
Sep 30, 2011 (14 hours ago)
Valve Didn't Forget About Portal 2's "Summer" DLC
If you haven't played Portal 2's co-op yet (like me!), now's probably a good time to fix that.
Valve just sent word that Portal 2's first set of downloadable content, dubbed Peer Review, will be released on every platform on October 4.
And if you've forgotten, this content won't cost you a dime.
Peer Review contains both single and co-op content, though the additional "story" bits appear to be relegated to the co-op expansion, which continues to follow P-Body, Atlas, and GLaDOS.
If you're playing solo, Valve's included a Challenge Mode with leaderboard functionality. Said Challenge Mode is also available for co-op play, though. Co-op! Co-cop! Co-op!
Sep 30, 2011 (13 hours ago)
Milestone achieved! Free Broken Sword for everyone!
Thank you everyone who helped us achieve the 6 million unique game downloads! You're the greatest, and here's a free Broken Sword for you!
Last week, during CD Projekt Fall 2011 Conference, we've launched a counter on the main page which indicated the number of unique games downloaded at GOG.com. Today that counter hit 6 million unique game downloads, and to celebrate this fact and to thank all of you at GOG.com, together with Revolution Software, we're lowering the price for first part of the acclaimed Broken Sword series to “free"! In order to receive the free copy of Broken Sword: Shadow of the Templars free, go to the gamecard and click on “download now”, at which point the game will be added to your game shelf.
The special offer for Broken Sword is valid until October 1, at 7:59 a.m. EDT (11:59 a.m. GMT), so be sure to grab it by then and don’t forget to share the news with all your friends!!!
UPDATE: In addition, we mentioned that the user who will make the 6 millionth download will receive the whole GOG.com catalogue for free! It was not a prank and the user who should start "wrestling" with his virtual shelf full of awesome classics is Dotur who downloaded Icewind Dale 2 exactly on 2011-09-29 at 07:39:43 EDT. Congratulations! We'll send you the gift certificate with all the games from the catalogue.
Last week, during CD Projekt Fall 2011 Conference, we've launched a counter on the main page which indicated the number of unique games downloaded at GOG.com. Today that counter hit 6 million unique game downloads, and to celebrate this fact and to thank all of you at GOG.com, together with Revolution Software, we're lowering the price for first part of the acclaimed Broken Sword series to “free"! In order to receive the free copy of Broken Sword: Shadow of the Templars free, go to the gamecard and click on “download now”, at which point the game will be added to your game shelf.The special offer for Broken Sword is valid until October 1, at 7:59 a.m. EDT (11:59 a.m. GMT), so be sure to grab it by then and don’t forget to share the news with all your friends!!!
UPDATE: In addition, we mentioned that the user who will make the 6 millionth download will receive the whole GOG.com catalogue for free! It was not a prank and the user who should start "wrestling" with his virtual shelf full of awesome classics is Dotur who downloaded Icewind Dale 2 exactly on 2011-09-29 at 07:39:43 EDT. Congratulations! We'll send you the gift certificate with all the games from the catalogue.
Sep 28, 2011 (3 days ago)
Free $2 Amazon MP3 Credit
What’s with the free $2 credits today? First CVS and now a free $2 Amazon mp3 credit
. All you need to do click the yellow button and enter code FALLMP3S. After half a dozen failed attempts, I had to end up copy & pasting the code. I can recall the starting lineup for every Seattle Mariners team over the past 20 years, but I guess my little peabrain can’t correctly remember a string of eight characters.
© Hey, It's Free!™ LLC. All rights reserved. Originally published by Ryan "Goob" Eubanks for Hey, It's Free! as Free $2 Amazon MP3 Credit.
. All you need to do click the yellow button and enter code FALLMP3S. After half a dozen failed attempts, I had to end up copy & pasting the code. I can recall the starting lineup for every Seattle Mariners team over the past 20 years, but I guess my little peabrain can’t correctly remember a string of eight characters.© Hey, It's Free!™ LLC. All rights reserved. Originally published by Ryan "Goob" Eubanks for Hey, It's Free! as Free $2 Amazon MP3 Credit.
Sep 27, 2011 (4 days ago)
Apple sends out invites for iPhone event on October 4th
It’s official: invitations for Apple’s iPhone event are now being sent to the media. As had been rumored, this year’s iPhone unveiling will be held on Apple’s campus in Cupertino, California as opposed to Apple’s standard venue, the Moscone Center in San Francisco. The press conference will begin at 10:00 a.m. Pacific, 1:00 p.m. Eastern, and BGR will be bringing you all the news as it breaks.
Sep 27, 2011 (4 days ago)
Obama recruiting analysts and R is one preferred skill
(This article was first published on RDataMining, and kindly contributed to R-bloggers)
Barack Obama is recruiting analysts for his 2012 re-election campaign.It is to analyze the campaign’s data to guide election strategy and
develop quantitative, actionable insights that drive decision-making.
R is mentioned as one of the tools to use.
Analytics positions to recruit include:
- Communications Analyst,
- Digital Strategy Analyst, and
- Statistical Modeling Analyst.
Job details and application are at “View Jobs” of http://www.barackobama.com/jobs.
Regards
Yanchang Zhao
RDataMining: http://www.rdatamining.com
Twitter: http://www.twitter.com/RDataMining
Group on Linkedin: http://group2.rdatamining.com
Group on Google: http://group.rdatamining.com
This article was kindly contributed to R-bloggers by RDataMining.
R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, lattice, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git) statistics (regression, PCA, time series, trading) and more...
Sep 27, 2011 (4 days ago)
Saudi woman driver to be lashed
Court in Saudi Arabia sentences woman to 10 lashes for defying the country's ban on female drivers.
Sep 28, 2011 (3 days ago)
Officially confirmed: iPhone 5 comes on October 4th
That's that then - the invitations have been sent and it has been officially confirmed that we are just a week away from seeing the next iPhone. The announcement will take place next Tuesday in a rather unusual place - the Apple campus in Cupertino. Normally those things happen in other venues in San Francisco, but this time Apple will be inviting journalists to its home. There's an outside...
The future is now. [ 
Sep 27, 2011 (4 days ago)
Simple, fast and useful MiniProfiler for ASP.NET MVC
MiniProfiler is very lightweight, simple, fast and useful profiler for ASP.NET websites including ASP.NET MVC. It is designed to help you find possible performance issues and have very nice and clear view over each operation that happens in your web applications.
MiniProfiler was created by the Stack Overflow guys for their internal use, but they have put it as an open source project under Apache License 2.0 for all ASP.NET and WCF developers! (Thanks guys!)
To get started using MiniProfiler, you have to install it first.
You have two options available:
Installation
1. Using NuGet Package Manager
- In VS.NET 2010, go to Tools –> Library Package Manager –> Manage NuGet Packages…
Install MiniProfiler.MVC3
Once installation is successful, both MiniProfiler will be ticked.
If you want to use MiniProfiler for Entity Framework too, then install the MiniProfiler.EF too.
2. Install manually from here (you have github clone too)
Setting up
Once you are done with installation, if you have used NuGet manager to install MiniProfiler, you are almost done
The new dlls added by the NuGet are marked:
Besides dlls, there is also a MiniProfiler.cs class inside App_Start folder
The next thing you need to do is to include MiniProfiler in the master layout page. Once you expand the Views –> Shared, you can see that with installing MiniProfiler there is _MINIPROFILER UPDATED Layout.cshtml that is an example master layout regarding how to include MiniProfiler in your Layout page.
Copy the marked line and add it to your actual _Layout.cshtml
In my example:
Using MiniProfiler
Now, run your application… you can see MiniProfiler is running in the top left corner:
If you want to see what does MiniProfiler includes for us, check View Source in your browser:
If you want to start the mini profiler for specific requests only (e.g. local requests), you can use MiniProfiler.Start() method. The best place to add this is in the Global.asax Application_BeginRequest.
Grouping Profiler Steps
Using MiniProfiler we can group profiling steps very easily. Yep, this might make your code in some segments a bit more dirty, but if you have clean code you should no worry…
To perform grouping by steps in your Controller, first add using MvcMiniprofiler; directive
Use the Step() method in using code block to create profiler step.
Example:
Then in my Products ActionResult add the following code:
Now add new View to display products list by right clicking somewhere above the code in Products() method and Add View with name Products.
In the view add the following code (just for the demo…):
once you click the button at the top-left corner you will get this:
Profiling Database Queries
To use MiniProfiler for profiling database queries, first you will need to de-comment one (or both) of the database related line/s inside App_Start/MiniProfiler.cs PreStart() method
First, I have rewritten the Products method with the following code:
I am using AdventureWorks database with EF. I have added one query that joins four tables. Now just run the application.
if we click on 1 sql, the MiniProfiler will give us some detailed info regarding generated SQL query and the time needed to execute and finish
If we have some query that is executing very long or we have multiple queries which create performance issues, MiniProfiler will give us warnings…
For example, lets add loop of executing the above query 50 times
bin
Summary
ASP.NET MVC MiniProfiler is a great tool that you must have in your toolset for building scalable, fast and performance optimized web applications. You can have clear view of what is causing performance issues in your application in almost all levels and layers.
For those that are interested to get access to the MiniProfiler source code and want to dig more, check this page.
I hope this was useful blog post for you.
Regards,
Hajan
Similar readings
MiniProfiler was created by the Stack Overflow guys for their internal use, but they have put it as an open source project under Apache License 2.0 for all ASP.NET and WCF developers! (Thanks guys!)
To get started using MiniProfiler, you have to install it first.
You have two options available:
Installation
1. Using NuGet Package Manager
- In VS.NET 2010, go to Tools –> Library Package Manager –> Manage NuGet Packages…
Install MiniProfiler.MVC3
Once installation is successful, both MiniProfiler will be ticked.
If you want to use MiniProfiler for Entity Framework too, then install the MiniProfiler.EF too.
2. Install manually from here (you have github clone too)
Setting up
Once you are done with installation, if you have used NuGet manager to install MiniProfiler, you are almost done
The new dlls added by the NuGet are marked:
Besides dlls, there is also a MiniProfiler.cs class inside App_Start folder
The next thing you need to do is to include MiniProfiler in the master layout page. Once you expand the Views –> Shared, you can see that with installing MiniProfiler there is _MINIPROFILER UPDATED Layout.cshtml that is an example master layout regarding how to include MiniProfiler in your Layout page.
Copy the marked line and add it to your actual _Layout.cshtml
In my example:
<!DOCTYPE html> <html> <head> <title>@ViewBag.Title</title> <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /> <script src="@Url.Content("~/Scripts/jquery-1.4.4.min.js")" type="text/javascript"></script> @MvcMiniProfiler.MiniProfiler.RenderIncludes() </head> <body> @RenderBody() </body> </html>
Using MiniProfiler
Now, run your application… you can see MiniProfiler is running in the top left corner:
If you want to see what does MiniProfiler includes for us, check View Source in your browser:
If you want to start the mini profiler for specific requests only (e.g. local requests), you can use MiniProfiler.Start() method. The best place to add this is in the Global.asax Application_BeginRequest.
Grouping Profiler Steps
Using MiniProfiler we can group profiling steps very easily. Yep, this might make your code in some segments a bit more dirty, but if you have clean code you should no worry…
To perform grouping by steps in your Controller, first add using MvcMiniprofiler; directive
using MvcMiniProfiler;Create instance of MiniProfiler by adding the MiniProfiler.Current that represents the currently running profiler in the HttpContextUse the Step() method in using code block to create profiler step.
Example:
Then in my Products ActionResult add the following code:
public ActionResult Products() { List<Product> listProducts = new List<Product>(); MiniProfiler profiler = MiniProfiler.Current; using (profiler.Step("Load Product Items", ProfileLevel.Info)) { System.Threading.Thread.Sleep(1000); //1 second sleep listProducts.Add(new Product() { ProductID = 1, Name = "Product 1", Price = 100 }); listProducts.Add(new Product() { ProductID = 2, Name = "Product 2", Price = 200 }); listProducts.Add(new Product() { ProductID = 2, Name = "Product 3", Price = 300 }); } using (profiler.Step("Add Products to List", ProfileLevel.Info)) { System.Threading.Thread.Sleep(2000); //2 seconds sleep ViewBag.Products = listProducts; } return View(); }In this example we have two profiler steps: Load Product Items and Add Products to List.
Now add new View to display products list by right clicking somewhere above the code in Products() method and Add View with name Products.
In the view add the following code (just for the demo…):
@{ ViewBag.Title = "Products"; Layout = "~/Views/Shared/_Layout.cshtml"; } <h2>Products</h2> <p> <ul> @foreach (var item in ViewBag.Products) { <li> @item.Name ($@item.Price) </li> } </ul> </p>Now run the web page and navigate to /Home/Products
once you click the button at the top-left corner you will get this:
Profiling Database Queries
To use MiniProfiler for profiling database queries, first you will need to de-comment one (or both) of the database related line/s inside App_Start/MiniProfiler.cs PreStart() method
//TODO: To profile a standard DbConnection: // var profiled = new ProfiledDbConnection(cnn, MiniProfiler.Current); //TODO: If you are profiling EF code first try: MiniProfilerEF.Initialize();In our example I will be using the EF Mini Profiler.
First, I have rewritten the Products method with the following code:
public ActionResult Products() { AdventureWorksEntities context = new AdventureWorksEntities(); ViewBag.Products = (from p in context.Products join pm in context.ProductModels on p.ProductModelID equals pm.ProductModelID join pmx in context.ProductModelProductDescriptionCultures on pm.ProductModelID equals pmx.ProductModelID join pd in context.ProductDescriptions on pmx.ProductDescriptionID equals pd.ProductDescriptionID select new ProductViewModel { ProductID = p.ProductID, Name = p.Name, Description = pd.Description.Substring(0, 200) }); return View(); }
I am using AdventureWorks database with EF. I have added one query that joins four tables. Now just run the application.
if we click on 1 sql, the MiniProfiler will give us some detailed info regarding generated SQL query and the time needed to execute and finish
If we have some query that is executing very long or we have multiple queries which create performance issues, MiniProfiler will give us warnings…
For example, lets add loop of executing the above query 50 times
public ActionResult Products() { AdventureWorksEntities context = new AdventureWorksEntities(); List<ProductViewModel> productList = new List<ProductViewModel>(); for (int i = 0; i < 50; i++) { productList.AddRange(from p in context.Products join pm in context.ProductModels on p.ProductModelID equals pm.ProductModelID join pmx in context.ProductModelProductDescriptionCultures on pm.ProductModelID equals pmx.ProductModelID join pd in context.ProductDescriptions on pmx.ProductDescriptionID equals pd.ProductDescriptionID orderby p.Name descending, p.ProductID ascending, pd.Description descending, pd.ModifiedDate descending select new ProductViewModel { ProductID = p.ProductID, Name = p.Name, Description = pd.Description.Substring(0, 200) }); } ViewBag.Products = productList; return View(); }Once we run the app, it will take few seconds to load…
bin
Summary
ASP.NET MVC MiniProfiler is a great tool that you must have in your toolset for building scalable, fast and performance optimized web applications. You can have clear view of what is causing performance issues in your application in almost all levels and layers.
For those that are interested to get access to the MiniProfiler source code and want to dig more, check this page.
I hope this was useful blog post for you.
Regards,
Hajan
Similar readings
Sep 28, 2011 (3 days ago)
Amazon launches tablet, new e-readers in full-on assault against Apple
Amazon.com dramatically increased the stakes in its ongoing battle with Apple (NASDAQ:AAPL) for digital media supremacy, officially launching its long-awaited, Android-powered tablet device as well as new Kindle e-reader devices.
The Amazon tablet, dubbed the Kindle Fire and priced at $199 (compared to $499 for Apple's cheapest iPad), effectively gives consumers a single, portable point of access to digital media initiatives including the Kindle e-book catalog, Amazon Appstore for Android, Amazon Instant Video and Amazon MP3, with all content backed up in the cloud. The Kindle Fire integrates with the Amazon Web Services platform and enables consumers to leverage free media offerings included within Amazon Prime, the $79 annual service that also offers unlimited two-day shipping on all products sold and processed by the e-commerce giant, excluding items offered by third-party sellers.
Unlike Apple, which relies on content from its iTunes digital media storefront and App Store to boost sales of hardware like the iPhone and iPad, Amazon is looking to the Kindle Fire to stoke consumer interest in its premium digital media ambitions.
"For 15 years we've been building our media business and it's become a $15 billion a year business," said Amazon founder and CEO Jeff Bezos during Wednesday's media event, stating that the company now offers more than 100 million feature films and television programs available to buy or rent. In addition, the Amazon MP3 storefront touts more than 17 million songs, some priced as low at 69 cents.
Kindle Fire also heralds the launch of Amazon Silk, a new browser promising to accelerate the mobile web user experience by caching and compressing data and images. Living both on the tablet and Amazon's own EC2 servers, Silk promises to consume less bandwidth than other tablet browsers, translating to faster page and multimedia load times. The Kindle Fire does not feature 3G network access, instead relying exclusively on Wi-Fi connectivity.
Amazon additionally rolled out the Kindle Touch, a new version of its signature e-reader enabling readers to turn pages of e-books or magazines by swiping the screen. The unit also boasts an on-screen keyboard. Pricing: $149 with Amazon Whispernet mobile connectivity or $99 for the Wi-Fi version. Amazon also unveiled a new, lighter version of the original Kindle priced at $79.
Amazon.com's Kindle Store offers more than 950,000 e-books, including the vast majority of current New York Times Bestsellers. Over 800,000 Kindle titles are priced at $9.99 or less. Amazon now sells more Kindle books than hardcover and softcover volumes combined: As of April 1, Amazon consumers purchase 105 Kindle titles for every 100 print books.
As of the second quarter of 2011, the Kindle brand leads the worldwide e-reader market with a 51.7 percent share, followed by Barnes & Noble's Nook at 21.2 percent, according to IDC data issued this month. IDC reports that the e-reader market experienced a seasonal sequential drop of 9 percent to 5.4 million units, although year-over-year growth reached 167 percent.
For more:
- read this Wired.com article
Related articles:
Amazon adds Fox to streaming video lineup as tablet launch nears
Report: Amazon in talks to roll out e-book library service
Amazon.com trialing website redesign optimized for tablet access
Report: Amazon's Android tablet, touchscreen Kindle coming in Q3
Amazon's Kindle 3G with Offers one-ups B&N's touchscreen Nook
Amazon Kindle e-book sales surpass all print titles combined
 |
| Click here to watch a video about the Kindle Fire. |
Unlike Apple, which relies on content from its iTunes digital media storefront and App Store to boost sales of hardware like the iPhone and iPad, Amazon is looking to the Kindle Fire to stoke consumer interest in its premium digital media ambitions.
"For 15 years we've been building our media business and it's become a $15 billion a year business," said Amazon founder and CEO Jeff Bezos during Wednesday's media event, stating that the company now offers more than 100 million feature films and television programs available to buy or rent. In addition, the Amazon MP3 storefront touts more than 17 million songs, some priced as low at 69 cents.
Kindle Fire also heralds the launch of Amazon Silk, a new browser promising to accelerate the mobile web user experience by caching and compressing data and images. Living both on the tablet and Amazon's own EC2 servers, Silk promises to consume less bandwidth than other tablet browsers, translating to faster page and multimedia load times. The Kindle Fire does not feature 3G network access, instead relying exclusively on Wi-Fi connectivity.
Amazon additionally rolled out the Kindle Touch, a new version of its signature e-reader enabling readers to turn pages of e-books or magazines by swiping the screen. The unit also boasts an on-screen keyboard. Pricing: $149 with Amazon Whispernet mobile connectivity or $99 for the Wi-Fi version. Amazon also unveiled a new, lighter version of the original Kindle priced at $79.
Amazon.com's Kindle Store offers more than 950,000 e-books, including the vast majority of current New York Times Bestsellers. Over 800,000 Kindle titles are priced at $9.99 or less. Amazon now sells more Kindle books than hardcover and softcover volumes combined: As of April 1, Amazon consumers purchase 105 Kindle titles for every 100 print books.
As of the second quarter of 2011, the Kindle brand leads the worldwide e-reader market with a 51.7 percent share, followed by Barnes & Noble's Nook at 21.2 percent, according to IDC data issued this month. IDC reports that the e-reader market experienced a seasonal sequential drop of 9 percent to 5.4 million units, although year-over-year growth reached 167 percent.
For more:
- read this Wired.com article
Related articles:
Amazon adds Fox to streaming video lineup as tablet launch nears
Report: Amazon in talks to roll out e-book library service
Amazon.com trialing website redesign optimized for tablet access
Report: Amazon's Android tablet, touchscreen Kindle coming in Q3
Amazon's Kindle 3G with Offers one-ups B&N's touchscreen Nook
Amazon Kindle e-book sales surpass all print titles combined
Sep 27, 2011 (4 days ago)
Sunspot 1302: It's big. It's bad. And it's coming our way
(PhysOrg.com) -- Behemoth sunspot 1302 unleashed another strong flare on Saturday morning--an X1.9-category blast at 5:40 am EDT. NASA's Solar Dynamics Observatory (SDO) recorded the extreme ultraviolet flash.
7:29 PM (11 hours ago)
The due-process-free assassination of U.S. citizens is now reality
(updated below)
Sep 29, 2011 (2 days ago)
Ron Suskind’s “Confidence Men”: A Terrible Book
No need to beat around the bush here: Ron Suskind’s “Confidence Men” is a terrible book. It’s not even remotely accurate, and contains surprisingly little new, original information.
The fundamental problem is that Suskind is stunningly ignorant of basic macroeconomics, financial markets, the financial crisis, and financial regulations — basically, all the subjects you’d need to understand in order to write a competent book about the Obama administration’s economic team. It also contains so many patently absurd, completely unsourced assertions that it’s really not a question of whether Suskind makes up some of his material, but rather how much of his material is made up.
Curiously, the articles slamming Suskind’s book almost all cite a series of minor errors (e.g., saying Tim Geithner was the “chairman” of the NY Fed rather than the “president”) in order to demonstrate Suskind’s incompetence. The book is riddled with much more major errors — errors which provide the foundation for his cooked-up narrative. To give you a flavor of what I’m talking about, here are a few representative examples.
Suskind’s Ignorance of Basic Macroeconomics/Monetary Policy
On page 22, Suskind claims that the idea of making interest rate cuts the primary tool of monetary policy was “an innovation of previous Fed chairman Alan Greenspan.” Yep, no central banker had ever thought to make interest rate cuts their primary policy tool before Greenspan. It gets worse though. Suskind then claims that Fed interest rate cuts only stimulate the economy because they “prompt everyone, everywhere, to roll over debts of all kinds by replacing whatever is on their balance sheet with its equivalent.” That’s it. Interest rates are cut, everyone refinances all their loans, and that’s it. No new loans being made, no inflation, nothing. This is what he thinks monetary policy is (and he repeats this several more times in the book, so it’s clearly how he thinks monetary policy works). This is not some trivial detail, either — how can Suskind be expected to understand the decisions that were being made if he can’t even understand how the Fed works on the most basic level?
Suskind’s Ignorance of the Repo Market
On pages 72–73, Suskind’s complete ignorance of the repo market causes him to badly misinterpret something Tim Geithner said to him — an interpretation which he then uses to further his very unflattering portrait of Geithner.
First of all, Suskind simply asserts, without any sourcing at all, that in August 2007, Geithner had only a “passing familiarity” with the repo market. The idea that the president of the NY Fed had only a “passing familiarity” with repos is absurd on its face. One of the NY Fed’s primary functions is implementing monetary policy, and one of the main ways it does this is by entering into — you guessed it! — repos. Did someone tell Suskind that Geithner only had a “passing familiarity” with repos? Clearly not, or else he would have sourced it, even anonymously. No, it’s clear that Suskind simply made it up in order to further hisfictitious unflattering portrait of Geithner.
Ironically, Suskind then proceeds to demonstrate his own ignorance of the repo market, in a discussion of Countrywide’s difficulties securing repo financing in August 2007. From the book (emphasis on the comically wrong parts added):
Suskind’s Ignorance of the Difference Between Creditors and Equity Holders
Finally, in the chapter on Geithner’s alleged refusal to resolve Citigroup (which very clearly never happened) Suskind writes:
This demonstrates quite clearly that Suskind lacked the knowledge or ability to understand the central dispute in his own book — the dispute that made headlines all over the country. How can Suskind be expected to understand what happened in this dispute if he couldn’t even understand what the dispute was about in the first place?
The answer, obviously, is that Suskind’s account of the dispute is not credible. (Bolstering that conclusion is the fact that the meeting in which Obama allegedly ordered the resolution of Citi has been reported on several times before, and every other journalist reported that Obama decided against resolving Citi.)
Anyone who is even remotely familiar with the financial crisis, or financial markets in general, would be able to catch 90% of Suskind’s mistakes/fabrications, so I don’t know how anyone who knows this material could possibly consider Suskind’s book credible. His account of the financial reform debate was, if possible, even more riddled with fundamental misunderstandings and mistakes, which renders his telling largely false. I was as close to the financial reform debate as anyone, and Suskind’s account is simply not what happened.
In any event, don’t waste your money.
The fundamental problem is that Suskind is stunningly ignorant of basic macroeconomics, financial markets, the financial crisis, and financial regulations — basically, all the subjects you’d need to understand in order to write a competent book about the Obama administration’s economic team. It also contains so many patently absurd, completely unsourced assertions that it’s really not a question of whether Suskind makes up some of his material, but rather how much of his material is made up.
Curiously, the articles slamming Suskind’s book almost all cite a series of minor errors (e.g., saying Tim Geithner was the “chairman” of the NY Fed rather than the “president”) in order to demonstrate Suskind’s incompetence. The book is riddled with much more major errors — errors which provide the foundation for his cooked-up narrative. To give you a flavor of what I’m talking about, here are a few representative examples.
Suskind’s Ignorance of Basic Macroeconomics/Monetary Policy
On page 22, Suskind claims that the idea of making interest rate cuts the primary tool of monetary policy was “an innovation of previous Fed chairman Alan Greenspan.” Yep, no central banker had ever thought to make interest rate cuts their primary policy tool before Greenspan. It gets worse though. Suskind then claims that Fed interest rate cuts only stimulate the economy because they “prompt everyone, everywhere, to roll over debts of all kinds by replacing whatever is on their balance sheet with its equivalent.” That’s it. Interest rates are cut, everyone refinances all their loans, and that’s it. No new loans being made, no inflation, nothing. This is what he thinks monetary policy is (and he repeats this several more times in the book, so it’s clearly how he thinks monetary policy works). This is not some trivial detail, either — how can Suskind be expected to understand the decisions that were being made if he can’t even understand how the Fed works on the most basic level?
Suskind’s Ignorance of the Repo Market
On pages 72–73, Suskind’s complete ignorance of the repo market causes him to badly misinterpret something Tim Geithner said to him — an interpretation which he then uses to further his very unflattering portrait of Geithner.
First of all, Suskind simply asserts, without any sourcing at all, that in August 2007, Geithner had only a “passing familiarity” with the repo market. The idea that the president of the NY Fed had only a “passing familiarity” with repos is absurd on its face. One of the NY Fed’s primary functions is implementing monetary policy, and one of the main ways it does this is by entering into — you guessed it! — repos. Did someone tell Suskind that Geithner only had a “passing familiarity” with repos? Clearly not, or else he would have sourced it, even anonymously. No, it’s clear that Suskind simply made it up in order to further his
Ironically, Suskind then proceeds to demonstrate his own ignorance of the repo market, in a discussion of Countrywide’s difficulties securing repo financing in August 2007. From the book (emphasis on the comically wrong parts added):
“That was really interesting,” Geithner later reflected, “because Countrywide had no idea what its exposure was, no understanding of what it had gotten into. And the fact that the market was unwilling to fund Treasuries if Countrywide was a counterparty was the best example of how fragile confidence was and how quickly it turned.”No, no, a thousand times no! Suskind completely misinterpreted what Geithner was saying. Countrywide wasn’t trying to use CDOs and MBSs to fund its repo book — it was trying to use Treasuries as collateral on repos, and counterparties were still refusing to roll over Countrywide’s repos. That’s why Geithner said it was “really interesting” — because market participants had become so scared of counterparty risk that they wouldn’t even lend against Treasuries (which in theory shouldn’t happen). Suskind evidently doesn’t know that Countrywide originated the subprime mortgages that went into the MBSs and CBOs; it wasn’t the end investor in the CDOs. But Suskind uses his horrible misinterpretation to paint Geithner as naïve and in denial about the depth of the problems in subprime MBSs and CDOs. (“Silly Geithner, he thought it was just a confidence problem!”) There’s a mistake like this on practically every page of the book (his misinterpretation of a memo by UBS’s Robert Wolf is classic in its utter wrongness too), and it all contributes to a narrative that, at the end of the day, is simply false.
Translation: the market would not even lend Countrywide cash to buy Treasury bonds, the safest investment in the firmament. CDOs, MBSs, or similar types of mortgage-based collateral that Countrywide was using to roll over its repo loans were suddenly seen as impossible to value or sell in August 2007, meaning that it was illiquid. The whole point of collateral is that it can be taken — the way the repo man repossesses your car after too many missed payments — and sold in liquid markets for cash. Collateral that is illiquid is no collateral at all. Countrywide’s intended use for the borrowed funds — to go out, like Sal Naro, and buy Treasuries and shore up its balance sheet or to use them as collateral for emergency bank loans — was irrelevant. Its collateral was no good.
Geithner, at the time and looking back, saw this strictly in terms of confidence.
Suskind’s Ignorance of the Difference Between Creditors and Equity Holders
Finally, in the chapter on Geithner’s alleged refusal to resolve Citigroup (which very clearly never happened) Suskind writes:
Geithner, on this point, would not budge. Debt was sacrosanct. No creditor would suffer. Bair was equally intransigent. Secured creditors, such as equity holders, of course, wouldn’t be wiped out, but they had to face consequences for lending money to an institution whose recklessness had led to its demise. They must, she said, “face some discipline.”Yes, you read that right: Suskind does not know the difference between secured creditors and equity holders. He apparently thinks that in a resolution of Citi, equity holders “wouldn’t be wiped out” (“of course,” he says). Again, this is not a trivial mistake — this is enormously important, because the entire debate over what to do with Citi revolved around the distinction between creditors and equity holders. The FDIC was (allegedly) advocating putting Citi’s commercial bank subsidiary into receivership, which would haircut creditors, whereas Geithner was advocating the stress tests, which in a worst-case scenario would lead to the government diluting equity holders, but not haircutting creditors.
This demonstrates quite clearly that Suskind lacked the knowledge or ability to understand the central dispute in his own book — the dispute that made headlines all over the country. How can Suskind be expected to understand what happened in this dispute if he couldn’t even understand what the dispute was about in the first place?
The answer, obviously, is that Suskind’s account of the dispute is not credible. (Bolstering that conclusion is the fact that the meeting in which Obama allegedly ordered the resolution of Citi has been reported on several times before, and every other journalist reported that Obama decided against resolving Citi.)
Anyone who is even remotely familiar with the financial crisis, or financial markets in general, would be able to catch 90% of Suskind’s mistakes/fabrications, so I don’t know how anyone who knows this material could possibly consider Suskind’s book credible. His account of the financial reform debate was, if possible, even more riddled with fundamental misunderstandings and mistakes, which renders his telling largely false. I was as close to the financial reform debate as anyone, and Suskind’s account is simply not what happened.
In any event, don’t waste your money.
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